In accordance with the requirements of citation databases, proper citation of publications appearing in our Quarterly should include the full name of the journal in Polish and English without Polish diacritical marks, i.e. "Eksploatacja i Niezawodnosc – Maintenance and Reliability".

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Structural analysis of hot forging dies with regard to their life

Many (sometimes antagonistic) factors affect the durability of tools used in forging. The life of dies depends on how well they were designed and made, including the thermochemical treatment and mechanical working, the sequence of steps in the thermal treatment and the forging process conditions (the tool and preform temperature, the charge material geometry, the process rate, the kind and amount of lubricant ensuring optimum tribological conditions). Another critical parameter is the kind of tool material. One should note that steel producers use their own procedures whereby the composition of the same steel may differ considerably between them. All this signifi cantly affects the fi nal quality of the product. An example of a product for which highly durable tools are required is a forging of the constant-velocity universal joint casing. Currently in large-lot production the casing is manufactured through cold and hot multioperation forging in closed dies with a complex deformation confi guration (forward and backward extrusion). Because of the very high unit pressures the effort of the die material is often so high that it results in the premature wear out and failure of the dies (life below 2000 units).

The possibilities of fertilization of winter oilseed rape a view to using its seed in production of bio-fuels. Part II. Ways of decreasing the costs of fertilization of winter oilseed rape

In the study possibilities of decreasing the costs of fertilization of winter oilseed rape were named. According to the authors optimization of soil reaction, application of fully balanced fertilization and chemical protection of plants, which ensure the achievement of high crops we!! result in a decrease in costs. Costs of fertilization may also be decreased directly, by providing some nutrients inform of dolomite sewage deposits.

Exploitation conditions of tools for hot working

Exploitation of tools for hot working in metal forming has significant influence on durability of them and quality of final product. For increase of exploitation conditions and durability, many research in this scope are worked. In this work theoretical and experimental results of thermomechanical conditions during forming process of screw spikes are presented.